Supporters say the initiative, which would require that animals have room to turn around, lie down, stand up and fully extend their limbs, is only right since the birds are killed for food, while opponents said it would adversely affect the the economy, The New York Times reported.
"If animals are going to be killed for food," said Wayne Pacelle, president and chief executive of the Humane Society of the United States, "the least we can do is treat them with decency and give them a semblance of life."
Julie Buckner, spokeswoman for Californians for Safe Food, the proposition's main opponent, says the initiative would "wipe out the California egg farmers and it's going to raise the food costs for consumers."
The $4 million Humane Society spent so far isn't chicken feed and is about half of what Pacelle thinks his side will spend before Nov. 4.
Californians for Safe Food had raised some scratch of its own -- more than $6.7 million by the end of September, federal election documents indicated.